Jaggies as aliasing or reconstruction phenomena: a tutorial

Jaggies (staircasing effects) along slanted lines or curved edges are omnipresent in digital imaging. They are so widespread in digital display devices that very often they are associated with the modern "computerized" world (and sometimes even intentionally introduced into artworks such as logos, advertisements, etc. to convey a modern "pixelized" look). Although this subject is not new, it still remains an important issue in the design of modern digital display and printing devices. In the classical literature, jaggies are often considered as aliasing artifacts; and yet some other references consider them instead as reconstruction artifacts. The present tutorial revisits this question and tries to elucidate the real nature of this phenomenon using Fourier-based considerations. It shows that the jaggies can be either aliasing artifacts due to poor sampling in capture, or the result of poor reconstruction; and it explains the implications thereof on the elimination of unwanted jaggies. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.